1. Field of the Invention
The present invention relates to a metal bonding method and a metal bonded structure.
2. Description of the Related Art
As an electrically conductive material used to form a wiring layer that is a component of a wiring substrate, or used to form an electrode surface of each electrode of a semiconductor chip or the like, copper is widely employed. As a conventional metal bonding method for electrically connecting a first bonding member to be bonded such as a wiring layer of a wiring substrate or the like to a second bonding member to be bonded such as an element electrode of a semiconductor chip, examples of such a conventional metal bonding methods include: a method in which the bonding faces are solder-bonded via solder; a method in which the bonding faces are bonded to each other by applying pressure while heating the bonding faces at a high temperature; and a method in which the bonding faces are activated by means of ion irradiation or the like in a vacuum so as to bond the bonding faces to each other; and so forth.